This section provides background information related to the present disclosure which is not necessarily prior art.
A desire to reduce the disturbance of tissue during surgical procedures drives methods and devices for surgical insertion such as catheter insertion. The term “catheter” as used in this document is a broad term that generally describes an elongated tube for insertion into a region of a subject. Catheters include, but are not limited to, drug delivery catheters, optical catheters, micro-catheters, host catheters, etc. A small diameter catheter can be inserted into a subject along an insertion trajectory towards a target location within the subject with a minimal disturbance to surrounding tissue.
A drawback to catheter insertion procedures is that the target location is hidden within the subject. Only a small opening in the subject allows insertion of the catheter. Imaging techniques such as computed tomography (CT), magnetic resonance imaging (MRI) ultrasonic imaging, etc. are helpful in guiding a surgeon or other operator to insert the catheter towards the target location within the subject. Insertion guide devices are also useful in guiding the surgeon.
Local mounted insertion guide devices are desirable, in contrast to other guide devices such as head frames as used in neurosurgery. Local mounted insertion guide devices are not as cumbersome as head frames due to their light weight and smaller size. The subject does not need to be immobilized after imaging as is the case with head frame technology. Local mounted insertion guide devices are also less expensive to manufacture. In many instances they are fabricated from plastic materials, and may be disposable. Further, in contrast to head frame technology, local mounted insertion guide devices allow a subject to break up a surgical procedure into at least two different visits to the hospital.
One visit may include imaging, where a number of reference points called fiducial markers are attached to a subject. A target location tissue is imaged along with the fiducial markers, thus giving the surgeon a reference location of the target location in relation to the fiducial markers. If the fiducial markers are left secured to the subject, the subject may now return home and complete a surgical procedure at a second visit because the fiducial markers preserve a reference frame for the surgeon to target and work with. This was not possible using head frame technology, where a subject needed to remain secured inside a head frame until after completion of the surgical procedure.
Using a local mounting technique, an insertion guide device is also attached to the subject. The function of the insertion guide device is to guide a catheter along an axis into the subject to the target location where a selected operation such as drug delivery, tissue removal, etc. is performed.
A difficulty with this procedure arises in location tolerance when the insertion guide device is attached to the subject. In neurosurgery, the insertion guide device is frequently attached to the subject's skull using bone screws. The screws may not center in their ideal location, making precise alignment of the insertion guide device difficult. Further, in neurosurgery, a cranial drill is used to open a burr hole in the subject's skull. Variations in skull material, as well as limitations of the drilling operation can cause the burr hole location to deviate from it's ideal location, and the burr hole is not always perfectly round.
What is needed is a method and device that can be adjusted to compensate for location errors of an insertion guide device. What is also needed is a method and device that can be adjusted to compensate for location errors in forming an opening in a subject. What is also needed is a method and device that in other ways, improves accuracy and ease of use of an insertion guide device.